iFi AC iPurifier

If you think of mains power as the ‘gasoline’ fuelling your audio system, the AC iPurifier is the product that ensures that it’s getting a clean, super premium blend to deliver the best possible audio fidelity.

The AC iPurifier is the latest in iFi audio’s stable of ‘power products’ designed to clean-up noisy mains supplies to audio systems. But this is no ordinary mains purifier. Technologically advanced, it’s Active Noise Cancellation (ANC) circuitry can eliminate far more noise across the frequency range than other passive devices. At -40dB, the difference is as distinct as night and day.

The retail price of the AC iPurifier is US$99 (ex-tax) or €109 /£99 (incl. tax).

First, we need to assure everyone that no snakes were hurt in the making of the iPurifier AC and no snake oil is contained in the product, the only oil in the production chain is crude oil that provides the basics for the plastics used.

Is there a scientific basis for the function of the device? Certainly and we can measure significant attenuation of noise on our 2.5GHz RF spectrum analyser between the AC iPurifier inserted and removed.

Indeed using additional plug in capacitors to filter HF noise is not exactly new and tends to be fairly effective at higher radio frequencies. However both practicality and safety agency requirements mean the values of these capacitors have to be fairly low and their effect is thus limited to higher frequencies, often > 1MHz.

In modern EMC (electro-magnetic compatibility) testing, typically frequencies below 150kHz are not included and frequencies below 500kHz allow relaxed levels of noise emission.

So many power supplies (even linear ones) release fairly large levels of noise in these frequency bands while passing all EMC standards. And it is often these lower RF noise components that cause trouble in audio systems and that are not easily filtered inside of audio gear either (no matter how diligent the designer is).

Going active allows us to address especially this < 500kHz noise rather effectively. This way the AC iPurifier achieves very wide bandwidth compared to simple passive capacitor based plug in devices.

Our ANC uses a simple analogue forward circuit, which is very fast and is backed by and hands over to capacitor based passive filtering for high frequencies. So there is no "noise echo" or any such problem.

Where the active circuit is fast enough to provide the opposing noise it kills noise, where it becomes too slow passive filtering through capacitors takes over.

The use of active noise suppression in mains powered systems is not exactly new, it has been used in large scale industrial applications for a while. It's application in domestic power systems to reduce mains born noise at frequencies much lower than possible using passive means and specifically to improve audio systems.

A note on the surge suppressor. These devices are in parallel with the mains, they are not resettable circuit breakers - instead their function is to limit any voltage between live/neutral by drawing extra current.

This current drawn to limit the voltage to safe levels may very well trip conventional current based circuit breakers, but the MOV is NOT a circuit breaker in itself. It also needs no re-set, if the surge is over it simply stops drawing current to limit the voltage.

Mains is the fuel that powers an audio system. Whether it is clean or not has a material impact upon quality and the user’s enjoyment of playback. iFi’s latest ‘power product’, the AC iPurifier, is no ordinary mains purification commodity.

Technologically advanced, it is an ACTIVE not a passive product, so it goes above and beyond and cancels far more noise across the frequency range than passive devices.

It is effective against both:

Common mode noise existing equally on both of the power pins, referenced to the earth pin.

Differential noise existing only between the two power pins – the net to earth is zero.

They are, in effect, flip sides of the same coin and are the bane of audio systems regardless of the type of power supply.

Nullifies noise others can’t reach

Compared to other generic noise filters, the AC iPurifier is superior because it is ACTIVE as opposed to passive. This enables it to achieve a far more comprehensive termination of noise across the frequency spectrum. As noise exists across the frequency range, this clearly means the AC iPurifier is unparalleled when it comes to neutralizing noise.

This chart compares the AC iPurifier (green line) which is ACTIVE to generic mains filters (red line) which are typically passive.

The effective noise reduction difference is as different as night and day.

MUCH better at up to -40dB and…

Effective across a wide frequency range, compared to passive filters which cover only very high RF frequencies.

Every audio system benefits from the AC iPurifier

The AC iPurifier is designed for use in ANY mains powered audio system and is very effective when added to modern audio systems that have an abundance of digital and analogue components. Typically these systems are powered from a plethora of mains plugs. All of these ‘wall warts’ can add their own unwanted noise issues and pollute the local mains supply. However, the design of the AC iPurifier is such that it is even more effective if several are used to ‘contain’ the same type of noisy sources.

Insert it into the AC mains wall outlet supplying the audio system OR insert into the mains extension block powering the audio system. Try both locations to determine which has the greatest impact on improving any noise issues.

Bristling with serious Power Technology

Compared to similar AC power products, the AC iPurifier can boast the technological features below, making it far more comprehensive and effective than its rivals.

Not only does the AC iPurifier carry out exceptional noise filtration, it also has several other features to go that extra mile:

Smart Diagnostics of Polarity – with both versions, EU and USA, it is possible to connect in the opposite polarity. The AC iPurifier detects a change and indicates this.

Smart Diagnostics of Earth – detects if the audio mains system it is inserted into has a Ground/Earth or not.

Intelligent Ground – by attaching the optional ground cable, it is possible to give any system an audio ground. Going directly to the AC iPurifier and into the mains, the Ground/Earth will be of the highest quality connection, making it the most effective at draining system noise.

Overvoltage Protection System means that electrical shorts, lightning strikes and surges in the mains will be detected and the AC iPurifier will clamp the voltage to safe levels to protect your AV components from damage.

To summarise:

The AC iPurifier is no ordinary mains filter.

Firstly, and most importantly, it purges the audio system mains of noise using both Active and Passive technologies to work across a wide frequency spectrum.

Secondly, it provides an intelligent Ground/Earth to reduce noise for cases of a “missing earth” causing problems with noise.

Thirdly, it checks and detects the local mains for Earth and Polarity anomalies.

Cons - Not ideal for every setup. It's better to have a well equilibrated audio system first.

This unit has been lent for review by iFi Audio and AT Consumers. By no means the thoughts and insights portrayed in this review are biased. These are my honest thoughts about it.

Introduction:

The iFi AC iPurifier is a compact, high-tech device that exhaustively reduces the noise of that power outlet into which you plug in your audio equipment.

How does it work?:

You plug it to the AC mains wall outlet that supplies the audio system or into the mains extension block for the audio system separating analogue digital equipment, and it automatically takes samples of the current from your socket to perform an optimal filtering.

Through the ANC technology (Active Noise Cancellation) and WPS (Wireless Purification System), the AC iPurifier calculates and sends a signal back to the socket that cancels the perceived noises. On the other hand, it protects the equipment against voltage surges, detects lack of ground in the system and if the polarity is correct. And if that were not enough, it has an intelligent ground connection (Intelligent Earth) that you can use to connect the ground of all your audio equipment, but it only works if necessary, further avoiding more ground loops.

Effects:

All that technical section is great, but it also has a great impact on the sound of our equipment, especially with low-quality switched power supplies (SMPS) or a dirty power outlet. There is greater realism in the music, greater consistency and a lower ground noise. Of course, if our audio setup had hiss, it will still have it, although it will be much more consistent and less accentuated.

Tests:

I tried the two configurations suggested by iFi and the second one proved to be more effective (in the middle of the strip). I own a somewhat rudimentary analogue equipment (amplifier and speakers) (a JVC UX2000RGD) that shows hiss at high volume but in the digital section I use an iFi iGalvanic3.0 (provided by AT Consumers ) next to my iFi micro iUSB3.0 and connected to my iFi micro iDSD with some great Meze 99 Classics. The results have been conclusive although I was somewhat skeptical at first.

Sound:

During this time testing it, I have appreciated more consistency in sound and something more body in music. About the noise level, maybe I notice it a tad minor but it is difficult to appreciate in my headphone setup, since the iGalvanic3.0 and the micro iUSB3.0 fulminan any noise. Through my speaker system (the JVC) I perceive that reduced noise level and greater realism much more clearly.

Conclusion:

If you have a Mid to High-End audio setup, the AC iPurifier is a great tool for improving consistency and realism in music without the need of replacing all power supplies and getting crazy at diagnosing ground and polarity issues. But don't forget that audio is like seeking a balanced and rich diet: Music is raw food, headphones and speakers are the chefs, the DAC sets the recipe, amplifiers cook the food and power supplies are the motivation and spirit behind everything. Motivation and spirit are key, but worthless without resources to take action.

Pros - Clean Power, Surge Protection, Improves found if the power was not in good shape, Solves Grounding Issues where possible, Pocket-Friendly Price for a power conditioner, Nice Design, Easy To Use

Cons - Improvements and results will vary with each system and situation, some systems are very prone to picking up noise in the mains, while others are less prone, You need to make sure you get the correct version for your country's power outlet.

iFi AC iPurifier - Power Immaculate

We reviewed quite a few types of audio devices so far, but this is the first time we dwell into a device that promises to purify the power that is fed to your audio devices. iFi AC iPurifier is here to clean your power and to give you a noise-free experience.

We knew for a while that iFi also designs power cleaning solutions, along with products like their iEMatch and Groundhog, which further help one get the best sound possible from the audio setup they already own. This being said, we are aware that reviewing a power cleaning solution might come as slightly controversial, so we'll try to stay as technical as possible, and follow along with real-world impressions as best as we can.

It should be noted that we have absolutely no affiliation with iFi, we am not receiving any incentive for this review. This review is not sponsored nor has been paid for by iFi or anyone else. We'd like to thank Hoomairah from iFi for providing the sample for the review. The sample was provided along with iFi's request for an honest and unbiased review. This review will be as objective as it is humanly possible, and it reflects our personal experience with iFi AC iPurifier. Every opinion expressed is ours and we stand by it. The purpose of this review is to help those interested in iFi AC iPurifier understand it better and know if it is a worthwhile investment for their audio collection.

iFi AC iPurifier is packaged in one of iFi's signature packages, made by materials which are trying to protect the environment, along with an elegant and unique presentation. The main box is white in color, and rectangular in shape, and it includes a hefty amount of information about iFi AC iPurifier, along with its purpose and a few other interesting bits of information.

iFi glued a "Noise Terminator" sticker on the box of the AC iPurifier, which we found quite cute and amusing. The device itself is based on the EU plug in our case, as we're currently situated in Bucharest and wouldn't be able to review AC iPurifier otherwise.

The package contains all the minimum extras necessary to keep the AC iPurifier running, beneath the manuals being the AC iPurifier unit itself, along with a bag of dehumidifying bag. Since it doesn't have any connector besides the power plug, nor needs anything else, the package is simple but elegant.

The AC iPurifier unit is seated in a foam cutout, which keeps it scratch and dust free during transport.

AC iPurifier is built like a tank, being a round, white cylinder which is meant to be plugged in the power mains of your audio setup. Our unit comes with the EU / Romanian standard power plug, but there are variations for other countries as well.

The top of the unit presents two LED lights, both of which can shine both green and red. The first light is the Polarity light, which indicates whether the AC iPurifier is plugged in the correct way, and we managed to experiment a bit with this, seemingly there being a correct and a wrong polarity possible in a power outlet. The second LED light on top of the iFi iPurifier is an "Earth" LED, which basically indicates whether the power outlet has grounding and whether that is wired properly. After experimenting with it, we noticed that the power outlets in Bucharest do have grounding, and that they are indeed wired correctly, allowing for iFi iPurifier to function correctly.

iFi iPurifier is meant to clean the AC power mains and to eliminate any noise which may arise as a result of irregular power. Since we are doing the tests in Bucharest, this is a place not known for clean or coherent power, and we have blackouts once or twice each month, a lot of industrial machinery being connected to the same power lines as our precious audio setups. In this situation, AC iPurifier comes in really handy, as we know we already have a wide variation in the power factor. Voltage surges might be an issue as well here, and iFi AC iPurifier is really handy to protect against those.

Technically, all power should come in clean and should be regulated strictly, but having very expensive and very sensitive speaker setups means that those can react to fine changes in voltage and power delivery, especially when it comes to speaker setups which are always connected to the power mains. If there is no grounding connection for those speakers, or if that grounding isn't done correctly, there will always be a humming noise coming from them, which can be quite quiet, or which can become quite loud, sometimes being considerably louder than the noise floor of a listening setup or of a song, resulting in actual noise which can be heard throughout a song.

To properly understand noise which can be induced by Voltage Variation, one first needs to understand how AC works, or how Alternative Current works. There is a wikipedia article explaining those things in detail here https://en.wikipedia.org/wiki/Mains_hum

AC iPurifier basically eliminates all of the issues that are brought on by AC and usage of high-gain, high-precision and sensitive Audio Equipment, being a very user friendly all-in-one solution for cleaning the mains.

Sound Quality

It is extremely complicated to say that we can take any kind of objective measurements of AC iPurifier with the equipment we have available at this moment, and even the best speakers we have right now, which are Edifier S1000DB, are not the most revealing or sensitive pieces of equipment there are, so the final results might be quite different for certain setups.

This time I had my girl help me with those tests. Since we could do the tests together, having the AC iPurifier connected to the same mains as my laptop, Monitor and my speaker setup, we tried to write our thoughts separately and then compiled them for this review.

All of the tests have been done using Edifier S1000DB Speaker setup, in a Bucharest apartment, at moderate to very high listening levels.

Starting with the bottom end, there is a small trace of more precision to the bass, especially when it comes to the upper mid-bass where it feels a tad cleaner and more precise with less bloat amounts.

In the midrange, each musical note seems to have a bit more definition, with every single musical note seemingly having better definition, each micro-texture from an electric guitar bearing a better definition and resolution, more details being presented to the listener, and with slightly less noise.

In the treble, the high notes seem to come a tad smoother with less overall noise and harmonic distortion. Since the tests were taken at very high listening levels, the integrated amplifier in S1000DB were clearly able to reveal those differences better, being under higher gain, having more voltage running through them, subsequently being more prone to noise and other similar issues.

The soundstage seems to be larger with AC iPurifier, the better resolution and detail in the midrange and treble helping shape the soundstage with a larger overall presentation, along with a deeper one. Since the S1000DB is a very specific speaker, AC iPurifier seems to also help it gain a blacker background, but then again, the power mains in Bucharest are not very clean, and other listeners might experience widely different results with different speaker setups and different levels of AC power inherent noise.

Another thing we noticed through our tests is that the timing / ADSR of each musical note seemed a tad better, with a bit better dynamics, but this might be a subsequent result of lowering the noise floor rather than a standalone result on its own. Microtextures, especially those presented in Mindless Self Indulgence synths seem to have considerably better resolution and to be better resolved. The guitars in Metallica's music bear quite the improvement, and the vocals in Pop music, like Melanie Martinez feel more natural and seem to be presented better.

The hum coming from S1000DB is also eliminated well when using AC iPurifier, but it should be noted that S1000DB doesn't have any Grounding in their power line, being a self-powered speaker without grounding, although our typical power plugs do have grounding, so AC iPurifier does a good job there as well, electronic music, like The Glitch Mob being presented with better bass definition. A different, better speaker / amplifier setup would present a different result but with self-powered speakers, the difference is there, at least in our experiment.

Value and Conclusion

At the end of the day, we need to carefully consider what we're presented with. iFi AC iPurifier is a very handy product, which can help eliminate all noise that is creeping into one's music from the power mains, along with the typical amplifier hum when the ground connection is missing.

It is not a very expensive product, being around 130$ in most places, and it offers quite a few services. Considering that most people own speaker setups much more expensive than this, AC iPurifier has a fairly good value and offers quite an excellent service.

One of the best parts about AC iPurifier is the surge protection, being like a second fuse you can add in your system to protect your investment and expensive speaker setup, Many people have setups which are worth thousands, iPurifier being surely welcome to help protect their investment.

At some point I considered giving the AC iPurifier to an uncle who has much more expensive speaker setups, but my girl told me that this one power cleaner has to stay in our system as she really likes the improvements it brings in our listening setup, and who am I to argue after all? I love having better protection and noise removal for both my listening experience, and the extra safety for my electronic devices.

At the end of the day, one should take iFi AC iPurifier for what it is, a very user-friendly solution which can bring serious improvements in sound, by cleaning the AC mains, which is able to analyse the polarity and the grounding of your home, along with offering one of the best prices for this type of products, most power conditioners costing many times the price of iFi AC iPurifier, without always offering the same amount of features or safety (the extra surge protection sure comes in handy).

We can totally recommend someone to look into iFi AC iPurifier as a power conditioner / mains noise removal / extra surge protection, and especially at loud listening levels and when the power is not exactly clean, this is surely going to have a positive impact on your overall listening experience, without costing a fortune.